Polycrystalline fiber KBS-5 with 0.5~1mm in diameter and up to 10 metersr long have been prepared by an extru-sion method. The effects of fiber length and the features of fiber end on the mea-sured value of fiber loss are studied. After comparing the losses of KRS-5 fibers prepared in different conditions, possible ways to further reduce the fiber are briefly disucussed.